Wooden pallets are used in great numbers for shipping, storage and handling of a wide variety of products in bulk. Due to heavy loads and rough handling, pallets are frequently destroyed or damaged and generally have a relatively short useful life. A continuous supply of substantial quantities of new replacement pallets is needed in industries which involve bulk storage and handling operations.
The methods of pallet construction have historically ranged from totally manual operations, using simple jig systems, to large, expensive, automated systems which are capable of the continuous production of pallets at automated speed.
One such automated system is disclosed by Mangan and May in U.S. Pat. No. 4,793,540 issued Dec. 27, 1988, now U.S. Pat. No. 4,793,540 and assigned to Accurate Tool, of Dayton, Ohio, which is prior art and hereby incorporated by reference herein. The Accurate system, while providing for rapid and continuous production of wooden pallets, has experienced some operational problems to which the present invention is directed.
One problem experienced by the Accurate system is the failure of its tool mounts to fully accommodate varying wood thicknesses, surface irregularities and the vibration and shock attendant to the operation of the nailing tools. The tool mounts of the Accurate system, being relatively immobile, may be jammed should the tool encounter an obstruction such as an improperly placed nail or other surface irregularity.
The tool mounts of the Accurate system were individually attached to a mounting bridge which was vertically adjustable. However, this did not prove to be effective in avoiding or accommodating the above-described problems.
It is therefore desirable to provide tool mounts for the nailing tools of a pallet system, such as the Accurate system, which are independently capable of accommodating dimensional irregularities in the pallet members, absorbing the shock associated with the operation of the nailing tools, and avoiding and accommodating nail jams and similar problems associated with the feeding of the pallet as it is constructed in such a system.
The continuous pallet building systems of the prior art have generally required that their transport systems make a momentary stop to allow the nailing tools to properly place the nail in the pallet. It is therefore desirable to produce a tool mount/nailing tool arrangement which will allow the nailing operation to be carried out while the transport system is in motion ("on the fly") to increase the efficiency of the machine while obviating the more complex control systems attendant to stop/start transport systems of the prior art.
Another problem associated with pallet building systems such as the Accurate system is in the alignment and registration of the pallet pieces prior to their being fed past the nailing stations for assembly. A system such as the Accurate system utilized a hold-down clamp of rigid material which was brought into sliding contact with the upper surfaces of the top slat pieces by a vertically actuating piston and cylinder combination. It was the purpose of the hold-down clamp to maintain the position of the yet unattached pallet pieces. The prior art system was undesirable because it encumbered the loading of the pallet parts, did not absorb vibration, and failed to properly move the top deck boards against the locating members.
It is therefore desirable to provide a hold-down clamp for such a pallet system which properly places the top deck boards against the locator members while accommodating surface variations, absorbing vibration, and allowing freer loading of the pallet parts.